Raul, when old Micro-Ridge starts to lose its ridge (when it wears out) that immediately affects on sound quality: it first gradually and soon rapidly looses nuances (accuracy) and dynamics (power), i.g. sound becomes lame and that can be heard easily, IME since mid 80´s. At 600 point there´s nothing left what Micro-Ridge´s superiority initially was all about, and I never went further simply because of stylus tip start to wear the record groove itself really. Today my maximum is that 500 hours (app. 750 LPs). I think all this applies for SAS Micro-Ridge as well ?
If new Dynavector´s Micro-Ridge´s ridge is 4 times thicker than old´s it will last 2000 h. The question is, how tall the new Micro-Ridge really is. Very interesting...